It seems to have "hotlink" prevention enabled. I've only gotten it work in the editor with pictures that are either uploaded via steemit, or afterwards by editing a post that it already has displayed as a blog entry and then adding the https://steemitimages/WIDTHxHEIGHT/ before the img URL. You'll get 404 or access denied when trying to use it otherwise.
It seems to have "hotlink" prevention enabled. I've only gotten it work in the editor with pictures that are either uploaded via steemit, or afterwards by editing a post that it already has displayed as a blog entry and then adding the https://steemitimages/WIDTHxHEIGHT/ before the img URL. You'll get 404 or access denied when trying to use it otherwise.